The present invention relates to toner metering blades used for metering toner in imaging processing equipment. The invention further relates to a novel process for manufacturing toner metering blades.
By way of background, toner metering blades are used in the toner cartridges of photocopy machines, laser printers, and other image processing equipment to perform the useful function of controlling the amount of toner that is transferred from a toner reservoir onto an image forming component. As is known, the image forming component, which is typically a photosensitive drum, is first rotated past an image forming area, where a latent image is formed thereon by laser imaging or other means. The image forming component is then advanced through the toner reservoir, where toner adheres to the portions of the image forming component that bear the latent image, forming a toner image pattern. As the image forming component continues to rotate, the toner image pattern is brought into contact with a print medium, such as paper, to which the toner is transferred to form a permanent image.
A typical prior art toner metering blade includes an elongated blade holder with a thin elongated blade element attached thereto. The blade holder mounts to a fixed structure on the toner cartridge such that a free edge portion of the blade element is positioned in close proximity to the moving image forming component, at a location where the image forming component enters the toner reservoir. The toner metering blade thus serves to remove excess toner remaining on the image forming component following a printing operation and prior to its re-entry into the toner reservoir. A strip made from silicone rubber or the like is usually secured to the toner blade at the free edge thereof. This provides the additional function of statically charging the image forming component to assist in the transfer of toner to the latent image.
In the past, toner metering blades have been manufactured by bonding the blade element to the blade holder in an adhesive bonding operation. Prior to or after the adhesive bonding operation, the silicone strip is applied to the free edge of the blade element in a separate manufacturing operation. In some cases, the silicone strip is a calendared strip that is placed on the blade element and secured thereto by appropriate curing. More recently, applicant's assignee has developed a technique for molding the silicone strip to the blade element. This provides a secure attachment between the blade element and the strip and obviates the strip calendaring, strip placement and strip curing steps referred to above.
A remaining deficiency of prior art toner metering blades is that several processing operations are still required to fabricate such products. Moreover, the relative placement of the blade element onto the blade holder is not controllable with complete precision. In particular, when the blade element and the blade holder are joined together with the soft adhesive sandwiched therebetween, the components can "float" relative to one another in three-dimensional space until the adhesive sets up. This can increase manufacturing tolerances to unsatisfactory levels.
It is with overcoming the foregoing deficiencies of the prior art that the present invention is concerned.